DUBAI/JERUSALEM/PALM BEACH, Florida, March 15 (Reuters) - U.S. officials responding to economic uncertainty over high oil prices predicted on Sunday that the U.S.-Israeli war on Iran would end within weeks and that a drop in energy costs would follow, despite Iran's assertion that it remains "stable and strong" and ready to defend itself. 

U.S. President Donald Trump threatened more strikes on Iran's main oil export hub Kharg Island over the weekend and said he was not ready to reach a deal to end the war which has shut off the vital Strait of Hormuz and shaken up global energy markets.

Trump has said Iran wants to negotiate, but Iranian Foreign Minister Abbas Araqchi on Sunday disputed that claim. 

"We have never asked for a ceasefire, and we have never asked even for negotiations," Araqchi told CBS' "Face the Nation" program. "We are ready to defend ourselves for as long as it takes."

With crude oil prices hovering around $100 a barrel, Trump administration officials later insisted that all signs point to a relatively quick end to the conflict. 

"This conflict will certainly come to the end in the next few weeks - could be sooner than that ... and we'll see a rebound in supplies and a pushing down of prices after that," U.S. Energy Secretary Chris Wright told ABC's "This Week" program.

Meanwhile, Araqchi sought to project an image of strength.

"It's not a war of survival. We are stable and strong enough," Araqchi told CBS. "We don't see any reason why we should talk with Americans, because we were talking with them when they decided to attack us, and that was for the second time."

With the war entering its third week, Trump said on Saturday that U.S. strikes had "totally demolished" much of Kharg Island and warned of more, telling NBC News on Saturday, "We may hit it a few more times just for fun."

The comments marked a sharp escalation from Trump, who had previously said the U.S. was targeting only military sites on Kharg, and dealt a blow to diplomatic efforts to end a war that has spread across the Middle East and killed more than 2,000 people, most in Iran and Lebanon.

Washington has brushed aside attempts by Middle Eastern allies to open talks, three sources told Reuters, and Iran's Revolutionary Guards said on Sunday they had fired more missiles at Israel and three U.S. bases in the region.

WAR, ENERGY CRISIS LOOK SET TO PERSIST

With global air transport heavily disrupted and no clear end in sight, Iran's ability to choke off traffic through the Strait of Hormuz, the conduit for a fifth of global oil and liquefied natural gas, has emerged as a decisive threat to the global economy.

Although some Iranian vessels have continued to pass, the passage has been effectively closed for most of the world's shipping since the United States and Israel attacked Iran on February 28 at the start of an intensive bombing campaign that has hit thousands of targets across the country.

The International Energy Agency on Sunday said oil from its emergency reserves will begin flowing to global markets soon, with member countries pledging to make available 411.9 million barrels.

Underlining the impact the war has had on energy infrastructure in the region, the global ship-refueling hub of Fujairah in the United Arab Emirates was closed after barrages on Saturday but resumed oil-loading operations on Sunday, a Fujairah-based industry source said.

Trump on Saturday called on China, France, Japan, South Korea, Britain and other countries impacted by the choking off of oil supplies through the Strait of Hormuz to join efforts to reopen shipping lanes.

The Financial Times reported that European Union foreign ministers would discuss expanding the EU's regional Aspides naval mission, which protects shipping against Houthi attacks in the Red Sea, to include the Strait of Hormuz.

France has been seeking to assemble a coalition to secure the strait once the security situation stabilizes, while Britain is discussing a range of options with allies to ensure the security of shipping, officials have said.

ISRAEL DENIES TALKS WITH LEBANON

Araqchi denied Iran was targeting civilian or residential areas in the Middle East and said it was ready to form a committee with its neighbours to investigate the responsibility for such strikes. 

But as the standoff continued, Iran's Revolutionary Guards said it had fired more missile and drone barrages at targets in Israel and at U.S. military bases in the region, where Saudi Arabia said it had intercepted 10 attacks.

Israel said its jets hit more targets in western Iran, including headquarters of the Revolutionary Guards and Basij militia forces in the city of Hamadan.

A source briefed on Israel's military strategy told Reuters that Israel had begun targeting roadblocks and bridges it believed Revolutionary Guards commanders were using. Iranian security forces detained dozens of people accused of sharing information with Israel, Iranian media reported.

Israel's Foreign Minister Gideon Saar rejected claims that Israel had told the United States it was running low on interceptors and dismissed a report that it could soon hold direct talks with Lebanon, where it has resumed its campaign against the Iranian-backed Hezbollah movement.